On Mon, 24 Apr 2023 at 09:20, syzbot <syzbot+28ed267c18c614a9376f@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 44149752e998 Merge tag 'cgroup-for-6.3-rc6-fixes' of git:/.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=147afc8fc80000 > kernel config: https://syzkaller.appspot.com/x/.config?x=710057cbb8def08c > dashboard link: https://syzkaller.appspot.com/bug?extid=28ed267c18c614a9376f > compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/7bfa303f05cc/disk-44149752.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/4e8ea8730409/vmlinux-44149752.xz > kernel image: https://storage.googleapis.com/syzbot-assets/e584bce13ba7/bzImage-44149752.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+28ed267c18c614a9376f@xxxxxxxxxxxxxxxxxxxxxxxxx It looks like it can lead to reading wrong/uninit ioprio in __get_task_ioprio. I think set_task_ioprio() should init ioprio before publishing and publish with a release store, __get_task_ioprio needs to use load acquire to ensure proper ordering. > ================================================================== > BUG: KCSAN: data-race in __get_task_ioprio / set_task_ioprio > > write to 0xffff888108c83888 of 8 bytes by task 15748 on cpu 0: > set_task_ioprio+0x23b/0x260 block/blk-ioc.c:291 > __do_sys_ioprio_set block/ioprio.c:124 [inline] > __se_sys_ioprio_set+0x272/0x5a0 block/ioprio.c:68 > __x64_sys_ioprio_set+0x43/0x50 block/ioprio.c:68 > do_syscall_x64 arch/x86/entry/common.c:50 [inline] > do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > read to 0xffff888108c83888 of 8 bytes by task 15749 on cpu 1: > __get_task_ioprio+0x1c/0x110 block/ioprio.c:150 > get_current_ioprio include/linux/ioprio.h:60 [inline] > init_sync_kiocb include/linux/fs.h:2003 [inline] > __kernel_write_iter+0xe2/0x380 fs/read_write.c:515 > dump_emit_page fs/coredump.c:885 [inline] > dump_user_range+0x258/0x480 fs/coredump.c:912 > elf_core_dump+0x1a73/0x1b90 fs/binfmt_elf.c:2142 > do_coredump+0xfeb/0x1840 fs/coredump.c:762 > get_signal+0xd65/0xff0 kernel/signal.c:2845 > arch_do_signal_or_restart+0x89/0x2a0 arch/x86/kernel/signal.c:306 > exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168 > exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204 > irqentry_exit_to_user_mode+0x9/0x20 kernel/entry/common.c:310 > irqentry_exit+0x12/0x40 kernel/entry/common.c:413 > exc_general_protection+0x339/0x4c0 arch/x86/kernel/traps.c:728 > asm_exc_general_protection+0x26/0x30 arch/x86/include/asm/idtentry.h:564 > > value changed: 0x0000000000000000 -> 0xffff8881049b5c90 > > Reported by Kernel Concurrency Sanitizer on: > CPU: 1 PID: 15749 Comm: syz-executor.5 Tainted: G W 6.3.0-rc6-syzkaller-00138-g44149752e998 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 > ================================================================== > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/00000000000071af7a05fa0fd8dc%40google.com.
